Electrically switchable multi-spot laser probe

ABSTRACT

In certain embodiments, a system may include a housing, one or more lenses, and a scanning system. The housing has an interior region. A lens is disposed within the interior region and transmits a light beam. The scanning system is disposed within the interior region and comprises a number of scanning cells, where each scanning cell comprises an electro-optical (EO) material. The scanning system performs the following for a number of iterations to yield a spot pattern: receive one or more voltages and electrically steer the light beam with the EO material from a current direction to a next direction in response to the voltages.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.13/308,875, filed Dec. 1, 2011, titled “ELECTRICALLY SWITCHABLEMULTI-SPOT LASER PROBE,” (now allowed), the disclosures of which areincorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to laser probes, and moreparticularly to an electrically switchable multi-spot laser probe.

BACKGROUND

Laser probes may be used for a variety of different purposes. In laserphotocoagulation, a laser probe may be used to cauterize blood vesselsat laser burn spots across the retina. Certain types of laser probesburn multiple spots at a time, which may result in faster and moreefficient photocoagulation. Some of these multi-spot laser probes splita single laser beam into multiple laser beams that have a laser spotpattern and deliver the beams to an array of optical fibers that have acorresponding fiber pattern. The optical fibers transmit the beams toyield a spot pattern at the target. In certain situations, however,these laser probes are not as efficient as desired.

BRIEF SUMMARY

In certain embodiments, a system may include a housing, one or morelenses, and a scanning system. The housing has an interior region. Alens is disposed within the interior region and transmits a light beam.The scanning system is disposed within the interior region and comprisesa number of scanning cells, where each scanning cell comprises anelectro-optical (EO) material. The scanning system performs thefollowing for a number of iterations to yield a spot pattern: receiveone or more voltages and electrically steer the light beam with the EOmaterial from a current direction to a next direction in response to thevoltages.

In certain embodiments, a method may include transmitting a light beamthrough one or more lenses disposed within an interior region of ahousing. One or more voltages are received by a scanning system disposedwithin the interior region. The scanning system has scanning cells,including a first scanning cell and a second scanning cell, where thefirst scanning cell is orthogonal to the second scanning cell, and eachscanning cell comprises an electro-optical (EO) material. The followingis performed by the scanning system for a number of iterations to yielda laser spot pattern at a number of optical fibers: receiving one ormore voltages and electrically steering the light beam with the EOmaterial from a current direction to a next direction in response to theone or more voltages.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present disclosure will now be described byway of example in greater detail with reference to the attached figures,in which:

FIG. 1 illustrates an example of an electrically switchable multi-spotlaser probe system according to certain embodiments;

FIGS. 2A and 2B illustrate an example of an electro-optical (EO)material according to certain embodiments;

FIGS. 3 and 4 illustrate a scanning cell of a probe system according tocertain embodiments;

FIGS. 5A through 5D illustrate an example of voltages applied to ascanning cell according to certain embodiments;

FIG. 6 illustrates an example of a pattern of diversion angles that mayyield a one-dimensional spot pattern according to certain embodiments;

FIG. 7 illustrates an example of a 2×2 spot pattern that may be formedby scanning cells according to certain embodiments; and

FIG. 8 illustrates an example of a 3×3 spot pattern that may be formedby scanning cells according to certain embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Referring now to the description and drawings, example embodiments ofthe disclosed apparatuses, systems, and methods are shown in detail. Thedescription and drawings are not intended to be exhaustive or otherwiselimit or restrict the claims to the specific embodiments shown in thedrawings and disclosed in the description. Although the drawingsrepresent possible embodiments, the drawings are not necessarily toscale and certain features may be exaggerated, removed, or partiallysectioned to better illustrate the embodiments.

FIG. 1 illustrates an example of an electrically switchable multi-spotlaser probe system 10 according to certain embodiments. In theillustrated example, system 10 includes a laser 20, a laser port 24, anadapter 30, an optical fiber connector 34, a strain relief 66, andcoupling devices 35 coupled as illustrated. Adapter 30 includes proximaladapter 31 and distal adapter 32. Disposed within adapter 30 are a lens40, a scanning system 42, and a lens 44. Optical fiber connector 34 mayinclude a ferrule 50 coupled to a connector body 51. A cylindricalinsert 52 may be disposed within optical fiber connector 34, and abundle of optical fibers 56 may be disposed within cylindrical insert52. Adapter 30, lens 44, and optical fiber connector 34 may form an airgap 46. Coupling devices 35 include a threaded cylinder 26, a retainingring 28, a spring 60, a coupling nut 62, and a C-clip 64.

In an example of operation, laser 20 emits a laser beam that is focusedtowards lens 40, which collimates the laser beam. Scanning system 42 anda controller (not shown) scan and switch the beam on and off (on/off) toyield a laser spot pattern that matches a fiber pattern of the bundle ofoptical fibers 56. Lens 44 refocuses the beam onto optical fibers 56.Optical fibers 56 transmit the beam through any suitable device, forexample, a laser probe. The beam may travel through the laser probe toany suitable target, such as the posterior region of an eye, such as ahuman eye. The beam forms a pattern at the target that matches the laserspot and fiber patterns. The beam may be used for any suitable purpose,such as for performing photocoagulation on the retina of the eye.

In certain embodiments, laser 20 may be any suitable light source thatcan generate a laser beam. Laser 20 may have a laser shutter that canswitch the beam on/off. Laser port 24 may be any suitable structure thatsupports certain components of system 10 such that laser 20 can direct alaser beam towards lens 40.

Adapter 30 is an example of a housing with a substantially cylindricalshape and a substantially cylindrical interior region. The interiorregion may have any suitable size and shape to house lenses 40 and 44and scanning system 42. Adapter 30 may have any suitable size, e.g., alength between 1 to 3 centimeters (cm) and an inner diameter between 200to 300 micrometers (μm). Adapter 30 may comprise any suitable material,such as a metal.

A lens 40 may be any suitable lens that can collimate a laser beam. Forexample, lens 40 may be a gradient index (GRIN) lens. Scanning system 42directs the laser beam in different directions, or scans the beam. Acontroller (not shown) instructs scanning system 42 to scan and laser 20to switch the beam on/off in a coordinated manner to yield a laser spotbeam. Scanning system 42 may include scanning cells that comprise anelectro-optical (EO) material that changes its refractive index inresponse to an applied electrical field. An example of an EO material isdescribed in more detail later with reference to FIGS. 2A and 2B.Accordingly, scanning system 42 may change the direction of a light beamin response to an applied voltage. Scanning system 42 is described inmore detail later with reference to FIGS. 3 through 5. Lens 44 may beany suitable lens that can refocus a multi-spot beam onto the focalplane defined by the proximal end faces of fibers 56. For example, lens44 may be a GRIN lens.

Optical fiber connector 34 couples optical fibers 56 to adapter 30 toallow optical fibers 56 to receive the laser beam from adaptor 30.Optical fibers 56 may be arranged at an aperture of optical fiberconnector 34 such that the ends of fibers 56 form a fiber pattern thatmatches the laser spot pattern. A laser spot pattern matches a fiberpattern if each beam spot hits or substantially hits an optical fiber 56to allow fibers 56 to optimally receive the beam. Any suitable beam spotand fiber patterns may be used. Examples of laser spot patterns aredescribed with reference to FIGS. 6 through 8.

Connector body 51 couples optical fiber connector 34 to adapter 30and/or devices connected to a probe. Connector body 51 may have anysuitable shape, e.g., a cylindrical shape within which optical fibers 56may be disposed. An optical fiber 56 is an optical waveguide that cantransmit light. An optical fiber 56 has a transparent core surrounded bya transparent cladding. Optical fiber 56 may comprise any suitabletransparent material, e.g., glass. Optical fiber 56 may have anysuitable size. For example, core 65 may have a diameter in the range of50 to 100 μm, such as approximately 75 μm, and cladding may have anouter diameter in the range of 80 to 150 μm, such as, 90 μm.

Coupling devices 35 couple together certain components of system 10. Forexample, threaded cylinder 26 and retaining ring 28 couple togetheradapter 30 and laser port 24. Spring 60, coupling nut 62, and C-clip 64couple together optical fiber connector 34 and adaptor 30.

FIGS. 2A and 2B illustrate an example of an electro-optical (EO)material according to certain embodiments. In the example, EO material80 is disposed between electrodes 82 (82 a-b). EO material 80 may be aliquid crystal (LC) material such as a polymer-dispersed liquid crystal(PDLC) material. In PDLC material, tiny circular or quasi-circular LCdroplets 90 with LC molecules 94 are immersed within a medium ofhardened polymer 92. Droplets 90 are immobilized within polymer 92, butLC molecules 94 within droplets 90 are free to rotate. In the absence ofan electric field, the orientations of LC molecules 94 tend to berandom, and the resulting effective refractive index of LC droplet 90 isn_(LC) (V=0)=n_(LCo) (FIG. 2A). As increasing voltage is applied to thePDLC material, LC molecules 94 tend to orient more and more along thedirection of the electric field, and the refractive index of droplet 90changes from n_(LCo) to n_(LC)(V). At maximum voltage V_(max), LCmolecules 94 have aligned with the electric field, and the refractiveindex of LC droplet 90 is n_(LC)(V_(max)) (FIG. 2B).

LC droplets 90 may be on the order of a wavelength of laser light orsmaller to avoid scattering light from the incident beam off LC droplets90. The PDLC material illuminated by the laser beam appears as aneffective medium with an effective refractive index n_(eff), which isdependent on the constant polymer refractive index n_(polymer) and thevoltage-dependent LC droplet effective refractive index n_(LC).Therefore, the effective index n_(eff) is also voltage-dependent andvaries from n_(effo) at 0 volts to n_(eff-max) at V_(max).

FIG. 3 illustrates a system 100 within probe system 10, and FIG. 4illustrates a scanning cell 110 of system 100. In the illustratedexample, system 100 is coupled to a controller 112 and laser 20. System100 includes a housing (such as adapter 30), one or more lenses 40and/or 44, a scanning system 42, and electrodes 114 (114 a-d) coupled asshown. Electrodes 114 are disposed within the housing. In certainembodiments, electrodes 114 may be disposed within an inner cylinder 115that is disposed within the housing. Inner cylinder 115 electricallyinsulates electrodes 114 and may comprise any suitable material, e.g.,ceramic.

Scanning system 42 comprises one or more scanning cells 110 (110 a-b),where each scanning cell 110 comprises an electro-optical (EO) material.Scanning system 42 performs the following to yield a spot pattern:receive one or more voltages and electrically steer the light beam withthe EO material from a current direction to a next direction in responseto the voltages. The beam may be steered to a diversion angle θ withrespect to a cylindrical axis of the housing. Diversion angle θ may haveany suitable value, such as a value in the range of 0 to 90 degrees.

Controller 112 steers light by applying different voltages acrossdifferent portions of scanning cell 110. In the example, scanning cell110 includes cover plate 142, electrode layer 144 disposed outwardlyfrom cover plate 142, OE element 146 disposed outwardly from electrodelayer 144, electrode layer 150 (with strip electrodes 152) disposedoutwardly from OE element 146, and a cover plate 156.

Cover plates 142 and 156 may comprise any suitable transparent material,such as glass, and may have any suitable shape and size, such as a flatplanar shape with a thickness in the range of 10 to 200 microns.Electrode layers 144 and 150 apply different voltages across OE element146. Electrode layers 144 may comprise any suitable conductive material,such as indium tin oxide (ITO). In certain embodiments, electrode layer150 comprises strip electrodes 152, where at least two strip electrodes152 apply different voltages. A strip electrode 152 may comprise anyconductive material, such as ITO. In certain embodiments, stripelectrodes 152 are individually addressable to yield a monotonicallychanging voltage vs. position pattern.

EO element 46 changes its refractive index in response to an appliedelectrical field. Accordingly, EO element 46 may change the direction ofa light beam in response to an applied voltage. EO element 46 maycomprise any suitable EO material, such as an optically transparentelectrically conductive (OTEC) material.

Controller 112 applies voltage to scanning cell 110 to steer a laserbeam. In certain embodiments, controller 112 may change the voltages tochange the direction of a light beam to yield the laser spot pattern.Controller 112 may also send instructions to laser 20 to switch on whenthe beam is directed to a location where a spot should be and to switchoff when the beam is not pointed at a spot location (for example, whenthe beam is moving from one spot location to another spot location).

One spot may be formed at each spot location of a spot pattern during ascan cycle. (In certain cases, a spot location may be visited more thanonce during a scan cycle.) The scan cycles may occur at any suitablerate. In certain embodiments, the scan rate may be determined withrespect to a burn time. In some cases, the scan rate may be selectedsuch that multiple scan cycles (such as 2, 3, 4, or more cycles) occurduring the burn time. For example, if the burn time is 200 milliseconds(ms), then the scan cycle may be 50 ms.

Controller 112 may form any suitable laser spot patterns of one or morespots. For example, an m×n pattern has m rows and n columns, where m=nor m>n, and m, n=1, 2, 3, . . . . As another example, a cross patternhas rows of spots radiating from a center point, which may or may nothave a spot. Examples of laser spot patterns are described in moredetail with reference to FIGS. 6 through 8. Moreover, a user mayinstruct controller 112 to form a different pattern in real time.

In certain embodiments, system 100 includes a scanning cell 110 thatsteers a beam in one dimension to yield a one-dimensional spot pattern.In other embodiments, system 100 includes two scanning cells 110 thatsteer a beam in two dimensions to yield a two-dimensional spot pattern.In these embodiments, two or more scanning cells 110 (110 a-b) may bepositioned in different directions to steer a light beam in twodimensions. For example, two scanning cells 110 may be positionorthogonally such that cell 110 a moves the beam along a firstcoordinate axis and cell 110 b moves the beam along a second coordinateaxis orthogonal to the first coordinate axis to allow fortwo-dimensional beam steering.

FIGS. 5A through 5D illustrate an example of voltages applied to ascanning cell 110 according to certain embodiments. The figures show howvoltages may be applied to scanning cell 110 to yield a monotonicallychanging refractive index versus position pattern.

FIG. 5A illustrates an example of a scanning cell 110 with stripelectrodes 152 and sides A and B. Different strip electrodes 152 mayapply different voltages to yield a voltage vs. position pattern. Anysuitable voltages may be applied. In the example of FIG. 5B, thevoltages monotonically change with respect to position from side A toside B, e.g., from a voltage in a range of 10 to 250 volts at side A toa voltage in a range of 0 to 5 volts at side B. The voltage vs. positionpattern yields a refractive index vs. position pattern. In the exampleof FIG. 5C, the refractive index monotonically changes with respect toposition from side A to side B, e.g., from a refractive index in a rangeof 1.5 to 1.8 at side A to a refractive index in a range of 1.4 to 1.6at side B. Accordingly, scanning cell 110 may operate similarly to awedge-shaped prism of FIG. 5D.

The time for a beam to pass through an optical element is inverselydependent on its optical thickness, which is product of the refractiveindex and thickness of cell 110 where the beam is traveling. In theillustrated example, the cell thickness is constant across the entirecell 110 and the refractive index varies across cell 110, so the opticalthickness, and thus the beam transit time, varies monotonically acrossthe cell. The refractive index is lower on the B side of the cell thanthe A side, so the beam passes through the B side of the cell fasterthan on the A side.

In certain situations, incident and emitted beams are collimated. When acollimated beam is normally incident on cell 110 of FIG. 5A, the beamreaches an outer surface 158 of plate 156 on the B side more quicklythan it does on the A side because the reflective index is lower on theB side than on the A side. According to optical principles, the beamemerging from surface 158 should be planar, with the wavefrontperpendicular to the beam direction. Thus, there is beam steering to theA side as the beam exits cell 140. Accordingly, rays between the planarwave front incident on the cell and the planar wave front exiting thecell have the same total optical path length. The same principle appliesfor the wedge prism, except in that case, the refractive index isconstant and the prism thickness varies with lateral position. But theend result is the same: the planar striped LC cell has the same effecton incident light as a constant-index wedge prism.

FIG. 6 illustrates an example of a pattern of diversion angles that maybe used to yield a one-dimensional laser spot pattern. In certainembodiments, the voltage applied to scanning cell 110 may be changed tochange diversion angle θ. In the example, graph 172 shows diversionangle θ changing with respect to time from θ_(i)=θ₁ to θ₄. The changesin diversion angle θ may yield a particular pattern of emitted light. Incertain embodiments, the laser power may be synchronized to be on whendiversion angle θ is at a desired angle θ_(i), but off when diversionangle θ transitioning between desired angles θ_(i). The resulting lightpattern may have clearer, less blurry, spots. In the example, graph 174shows the pattern of emitted light resulting from the synchronizedchanges in diversion angle θ and the transmitted laser power.

FIG. 7 illustrates an example of an m×n=2×2 spot pattern that may beformed by scanning cells 110 (110 a-b). In the example, the scan angleof a laser beam from a scanning cell 110 is between +θ_(max) and−θ_(max). Controller 112 controls cells 110 and laser 20 so that thebeam jumps rapidly between spot locations 210 (a-d), but remains at eachspot location 210 for a dwell time to yield a beam spot 212. In certainembodiments, controller 112 may stop the beam when the scanning systemis changing directions, and start the beam when the scanning system isat a fixed position. “Stopping the beam” may refer to any action thatstops the beam, such as blocking or turning off the beam. “Starting thebeam” may refer to any action that starts the beam, such as unblockingor turning on the beam. Controller 112 may perform these actions byinstructing laser 20 to perform these actions.

The beam may visit spot locations 210 in any suitable order. Forexample, the beam may jump between spot locations 210 a and 210 b,remain at spot location 210 b for a dwell time, jump between spotlocations 210 b and 210 c, remains at spot location 210 c for a dwelltime, etc. The resulting pattern is a 2×2 square array that may bedirected to fibers with a similar 2×2 proximal fiber pattern. The beamtravels through the fibers and through a distal fiber pattern to createa beam pattern (which typically matches the distal fiber pattern) on thetarget, such as a retina. The distal fiber pattern may be any suitablepattern, e.g., a pattern of p=m×n spots, such as a 2×2 pattern or a 1×4pattern.

FIG. 8 illustrates an example of an m×n=3×3 spot pattern that may beformed by scanning cells 110 (110 a-b). Controller 112 controls cells110 and laser 20 so that the beam jumps rapidly between spot locations220 (a-d), but remains at each spot location 220 for a dwell time toyield beam spot 222. The beam may visit spot locations 220 in anysuitable order. For example, the spot locations may be visited in theorder 220 a, 220 b, 220 c, . . . , 220 i. The resulting pattern is a 3×3square array that may be directed to fibers with a similar 3×3 proximalfiber pattern and then travel through the fibers to a distal fiberpattern. The distal fiber pattern may be any suitable pattern, such as a3×3 pattern or a 1×9 pattern.

Any suitable dwell time may be used. In certain embodiments, the dwelltime may be selected with respect to the scan time and number of spotsin the scan patter. For example, if the scan time for a four-spotpattern is 40 ms, the dwell time may be approximately 10 ms. In certainembodiments, controller 112 may be configured to use different dwelltimes for different situations and for different spot locations of thesame pattern. For example, certain spots of a pattern that travelfarther to the target may be larger, so they may have less irradiancethan the spots that do not travel as far. Thus, these spots may have alonger dwell time to compensate for the reduced irradiance.

A component (such as controller 112) of the systems and apparatusesdisclosed herein may include an interface, logic, memory, and/or othersuitable element, any of which may include hardware and/or software. Aninterface can receive input, send output, process the input and/oroutput, and/or perform other suitable operations. Logic can perform theoperations of a component, for example, execute instructions to generateoutput from input. Logic may be encoded in memory and may performoperations when executed by a computer. Logic may be a processor, suchas one or more computers, one or more microprocessors, one or moreapplications, and/or other logic. A memory can store information and maycomprise one or more tangible, computer-readable, and/orcomputer-executable storage medium. Examples of memory include computermemory (for example, Random Access Memory (RAM) or Read Only Memory(ROM)), mass storage media (for example, a hard disk), removable storagemedia (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)),database and/or network storage (for example, a server), and/or othercomputer-readable media.

In particular embodiments, operations of the embodiments may beperformed by one or more computer readable media encoded with a computerprogram, software, computer executable instructions, and/or instructionscapable of being executed by a computer. In particular embodiments, theoperations may be performed by one or more computer readable mediastoring, embodied with, and/or encoded with a computer program and/orhaving a stored and/or an encoded computer program.

Although this disclosure has been described in terms of certainembodiments, modifications (such as changes, substitutions, additions,omissions, and/or other modifications) of the embodiments will beapparent to those skilled in the art. Accordingly, modifications may bemade to the embodiments without departing from the scope of theinvention. For example, modifications may be made to the systems andapparatuses disclosed herein. The components of the systems andapparatuses may be integrated or separated, and the operations of thesystems and apparatuses may be performed by more, fewer, or othercomponents. As another example, modifications may be made to the methodsdisclosed herein. The methods may include more, fewer, or other steps,and the steps may be performed in any suitable order.

Other modifications are possible without departing from the scope of theinvention. For example, the description illustrates embodiments inparticular practical applications, yet other applications will beapparent to those skilled in the art. In addition, future developmentswill occur in the arts discussed herein, and the disclosed systems,apparatuses, and methods will be utilized with such future developments.

The scope of the invention should not be determined with reference tothe description. In accordance with patent statutes, the descriptionexplains and illustrates the principles and modes of operation of theinvention using exemplary embodiments. The description enables othersskilled in the art to utilize the systems, apparatuses, and methods invarious embodiments and with various modifications, but should not beused to determine the scope of the invention.

The scope of the invention should be determined with reference to theclaims and the full scope of equivalents to which the claims areentitled. All claims terms should be given their broadest reasonableconstructions and their ordinary meanings as understood by those skilledin the art, unless an explicit indication to the contrary is madeherein. For example, use of the singular articles such as “a,” “the,”etc. should be read to recite one or more of the indicated elements,unless a claim recites an explicit limitation to the contrary. Asanother example, “each” refers to each member of a set or each member ofa subset of a set, where a set may include zero, one, or more than oneelement. In sum, the invention is capable of modification, and the scopeof the invention should be determined, not with reference to thedescription, but with reference to the claims and their full scope ofequivalents.

What is claimed is:
 1. A method comprising: transmitting a light beamthrough a plurality of lenses disposed within an interior region of ahousing; receiving, by a scanning system disposed within the interiorregion, voltages, the scanning system comprising a plurality of scanningcells comprising a first scanning cell and a second scanning cell, thefirst scanning cell orthogonal to the second scanning cell, eachscanning cell comprising an electro-optical (EO) material; andperforming, by the scanning system, the following for a number ofiterations to yield a laser spot pattern at a plurality of opticalfibers: receiving a plurality of voltages; and electrically steering thelight beam with the EO material from a current direction to a nextdirection in response to the one or more voltages.
 2. The method ofclaim 1, each scanning cell comprising: a first electrode layer; an EOelement comprising the EO material and disposed outwardly from the firstelectrode layer; and a second electrode layer disposed outwardly fromthe EO element and comprising a set of strip electrodes, a first stripelectrode configured to apply a different voltage than a voltage appliedby a second strip electrode.
 3. The method of claim 1, the EO materialcomprising a polymer-dispersed liquid crystal (PDLC) material.
 4. Themethod of claim 1, the receiving the voltages comprising: receiving thevoltages by at least two electrodes of the scanning cell, each electrodecomprising an optically transparent electrically conductive (OTEC)material.
 5. The method of claim 1, further comprising: applying, by acontroller, the voltages to yield the spot pattern.
 6. The method ofclaim 1, the number of iterations equal to a number of spots of thepattern.
 7. The method of claim 1, the performing the following for anumber of iterations to yield the laser spot pattern further comprising:directing the light beam to a current laser spot location of the laserspot pattern for a dwell time; and steering the light beam to a nextlaser spot location of the laser spot pattern.
 8. The method of claim 1,further comprising: starting, by a controller, the light beamsubstantially when the scanning system is starting to direct the lightbeam to a current laser spot location of the laser spot pattern for adwell time; and stopping, by the controller, the light beamsubstantially when the scanning system is steering the light beam to anext laser spot location of the laser spot pattern.